Field of the Invention
This invention relates generally to a lateral vehicle object detection system and, more particularly, to an object detection system which identifies the unique motion signature of wheels in radar point data to locate a remote vehicle's wheels, and uses the remote vehicle wheel locations to accurately determine the position, orientation and velocity of the remote vehicle, and simultaneously calibrate radar sensor alignment.
Discussion of the Related Art
Object detection systems, also known as object sensing systems, have become increasingly common in modern vehicles. Object detection systems can provide a warning to a driver about an object in the path of a vehicle. Object detection systems can also provide input to active vehicle systems—such as Adaptive Cruise Control, which controls vehicle speed to maintain appropriate longitudinal spacing to a leading vehicle, and Rear Cross Traffic Avoidance systems, which can provide both warnings and automatic braking to avoid a collision with an object behind a host vehicle when the host vehicle is backing up.
Object detection systems use one or more sensors, which may be radar, lidar, camera, or other technologies, to detect the presence of an object in or near the path of a host vehicle. Software is used to track the relative motion of objects over time, determine if the objects are moving or stationary, determine what each object is likely to be (another vehicle, a pedestrian, a tree, etc.), and determine whether each object poses a collision threat to the host vehicle.
However, even with multiple object sensing inputs, such as radar and camera, it is not always possible to accurately estimate the heading of a remote vehicle or object, especially if the remote vehicle or object is moving in a predominantly lateral or tangential direction relative to the host vehicle. Furthermore, in some situations, it is difficult to accurately correlate radar point data with camera image data. Fusion techniques are needed which provide accurate two-dimensional velocity of remote vehicles and objects, using object data from a camera and two radar sensors.